Ventilation interface for sleep apnea therapy

ABSTRACT

The ventilation interface for sleep apnea therapy interfaces a ventilation device to the patient&#39;s airways. The ventilation interface includes a pair of nasal inserts made from flexible, resilient silicone which are oval shaped in cross-section and slightly tapered from a base proximal the ventilation supply to the distal tip end. A bead flange is disposed about the exterior of each insert at the distal end of the insert. A bleed port for release of exhaled air is defined through a conical vent projecting normally to the path of the incoming air flow, and continues through a nipple extending to the exterior of the air conduit. In one embodiment, a pair of nasal inserts are integral with a nasal cannula body, with bleed ports axially aligned with each insert. In another embodiment, each insert is independently connected to a separate, thin-walled, flexible supply line.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of and claims priority under35 U.S.C 120 to application Ser. No. 10/610,594, filed Jul. 2, 2003.Further, application Ser. No. 10/610,594 is a continuation-in-part ofapplication Ser. No. 09/524,371, filed Mar. 13, 2000, all to Thomas J.Wood, the disclosures of which are incorporated by reference herein intheir entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to ventilation devices, and particularlyto a ventilation device having a nasal inserts which are inserted intothe nostrils and seal against the nostrils without the aid of harnesses,head straps, adhesive tape or other external devices, and havingexhalation ports designed to eliminate whistling noises, the ventilationinterface having particular utility in various modes of therapy forobstructive sleep apnea.

2. Description of the Related Art

Sleep apnea is a potentially lethal affliction in which breathing stopsrecurrently during sleep. Sleep apnea may be of the obstructive type(sometimes known as the pickwickian syndrome) in which the upper airwayis blocked in spite of airflow drive; the central type with decreasedrespiratory drive; or a mixed type. Breathing may cease for periods longenough to cause or to exacerbate cardiac conditions, and may beaccompanied by swallowing of the tongue. Sleep apnea frequently resultsin-fitful periods of both day and night sleeping with drowsiness andexhaustion, leaving the patient physically and mentally debilitated.

In recent years it has been found that various forms of positive airwaypressure during sleep can be an effective form of therapy for the apneasufferer. Ventilation can be applied in the form of Continuous PositiveAirway Pressure (CPAP) in which a positive pressure is maintained in theairway throughout the respiratory cycle, Bilevel Positive AirwayPressure (BiPAP) in which positive pressure is maintained duringinspiration but reduced during expiration, and Intermittent MechanicalPositive Pressure Ventilation in which pressure is applied when anepisode of apnea is sensed. Positive airway pressure devices havetraditionally employed either a face mask which only covers thepatient's nose, or nasal pillows as the interface between theventilation device and the patient's airway. However, there are problemswith both of these interfaces.

The face mask requires a harness, headband, or other headgear to keepthe mask in position, which many patient's find uncomfortable,particularly when sleeping. The face mask must seal the mask against thepatient's face, and may cause irritation and facial sores, particularlyif the patient moves his head while sleeping, causing the mask to rubagainst the skin. Face masks are also position dependent, and may leakif the mask changes position with movement of the patient's head. Theface mask applies pressure to the sinus area of the face adjacent to thenose, causing the airways to narrow, thereby increasing the velocity offlow through the airway, but decreasing the pressure against the nasalmucosal walls. This strips moisture from the mucosal wall duringinspiration, thereby causing drying and a burning sensation. Thesefactors will often result in the patient's removal of the mask anddiscontinuance of positive airway pressure therapy.

Nasal pillows are pillowed style nasal seals which are pressed againstthe inferior portion of the nares to close the nostril openings. Nasalpillows require a headband or harness to maintain the pressure,resulting in the same patient discomfort noted with face masks. Nasalpillows have about a 0.25″ internal diameter at the nasal entry portwhere the seal is made. Therefore, pressurized air must pass through aconstricted port, increasing the velocity of airflow, with resultantdrying and burning of the nasal airways. The narrowed interface diameterof the nasal pillows causes a pressure drop, which is directlyproportional to the drop in the number of available air molecules withinthe closed system. It is the volume of air molecules at the area in thepatient's throat where the apneic events appear that is needed tocorrect apnea. The narrower the airways or the internal diameter of thenasal interface, the lower the volume of air molecules that will beavailable and the greater the driving pressure that is required to meetthe volume demand. An increase in driving pressure does not fullycompensate for the loss in the number of air molecules available.

A further problem with existing ventilation devices is that the carbondioxide bleed ports for venting exhaled gases are noisy on both nasalface masks and nasal pillows. The whistling noise that occurs whileutilizing such devices can prove quite annoying to the patient,awakening the patient and causing the patient to discontinue use of theventilation device.

A number of devices have been proposed which include a ventilationinterface for supplying gases to be inhaled, for collecting exhaledgases, or for mounting sensors for measuring or monitoring respiratoryfunction.

U.S. Pat. Nos. 5,335,654 and 5,535,739, issued on Aug. 9, 1994 toRapoport and Jul. 16, 1996 is to Rapoport et al., respectively, describea CPAP system using a conventional nasal mask, the innovation comprisinga flow sensor in the input line connected to a signal processor todetermine the waveform of airflow, which is connected to a flowcontroller to adjust the pressure of airflow as required. U.S. Des. Pat.No. 333,015, issued Feb. 2, 1993 to Farmer et al. shows an ornamentaldesign for a nasal mask. U.S. Des. No. 262,322, issued Dec. 15, 1981 toMizerak, shows an ornamental design for a nasal cannula with a mouthmask.

U.S. Pat. No. 4,782,832, issued Nov. 8, 1988 to Trimble et al.,discloses nasal pillows held in the patient's nose by a harnessarrangement, the device having a plenum with two accordion or bellowsshaped nipples for fitting against the nostril openings. U.S. Pat. No.4,774,946, issued Oct. 4, 1988 to Ackerman et al., teaches a nasal andendotracheal tube apparatus for administering CPAP to infants, the nosetubes having a bulbous portion for seating in the pares of an infant anda headband with a Velcro® closure for supporting the cannula and supplytubes.

U.S. Pat. No. 5,269,296, issued to Landis on Dec. 14, 1993, and U.S.Pat. Nos. 5,477,852 and 5,687,715, issued to Landis et al. on Dec. 26,1995, and Nov. 18, 1997, respectively, describe CPAP devices for thetreatment of sleep apnea with relatively stiff or rigid nasal cannulaeor prongs surrounded by inflatable cuffs to retain the cannulae in thepares, but which also may be supplemented by an inflatable head harnessto position the cannulae and hold them in place, the two cannulae beingjoined by a conduit having vent holes to vent exhaled air. U.S. Pat. No.5,533,506, issued Jul. 9, 1996 to the present inventor, discloses anasal tube: assembly in which the tubes are tapered, frustro-conicalassemblies with a soft membrane over the distal tip and a washer at thebase of the nasal tube to prevent the tubes from falling through asupport bar connected to a harness, the nasal tubes forming a positiveseal with the inside of the nostrils to prevent the escape of gases.

U.S. Pat. No. 5,682,881, issued Nov. 4, 1997 to Winthrop et al., shows anasal cannula for CPAP therapy with cone shaped nasal prongs in whichthe cannula is secured to the patient's upper lip by adhesive tapestrips. U.S. Pat. No. 4,915,105, issued Apr. 10, 1990 to Lee, teaches aminiature respiratory breather apparatus in which relatively stiff orrigid nasal tubes have elastomeric packings for sealing the tubes in thenares.

Several patents describe improvements to nasal cannulae, but withoutsealing the nose tubes against the nostrils to prevent leakage of gas,including: U.S. Pat. No. 3,513,844, issued May 26, 1970 to Smith (metalstrip in cannula cross-tube to retain configuration matching patient'slip); U.S. Pat. No. 4,106,505, issued Aug. 15, 1978 to Salter et al.(cannula body with ends extending upward and rearward); U.S. Pat. No.4,915,104, issued Apr. 10, 1990 to Marcy (clasp with lanyard supportingsupply tubes to ease pressure on ears); U.S. Pat. No. 5,025,805, issuedJun. 25, 1991 to Nutter (cylindrical soft sponge cuff around supplytubes to ease pressure and prevent skin injuries); U.S. Pat. No.5,046,491, issued Sep. 10, 1991 to Derrick (device for collecting gasesexhaled from both nose and mouth); U.S. Pat. No. 5,335,659, issued Aug.9, 1994 to Pologe (device for mounting optical sensor on nasal septum);U.S. Pat. No. 5,509,409, issued Apr. 23, 1996 to Weatherholt (nasalcannula with face guards); U.S. Pat. No. 5,572,994, issued Nov. 12, 1996to Smith (rotatable coupling in supply tubing); U.S. Pat. No. 5,636,630,issued Jun. 10, 1997 to Miller et al. (support for supply tubes); U.S.Pat. No. 5,704,916, issued Jan. 6, 1998 to Byrd (novel head strap fornasal cannula); and U.S. Pat. No. 5,704,799, issued Apr. 21, 1998 toNielsen (device with one-way flow through cannula and flow restrictor toequalize flow into two nose members).

None of the above inventions and patents, taken either singly or incombination, is seen to describe the instant invention as claimed. Thusa ventilation interface for sleep apnea therapy solving theaforementioned problems is desired.

SUMMARY OF THE INVENTION

The ventilation interface for sleep apnea therapy interfaces aventilation device which provides positive airway pressure (eithercontinuous, bilevel, or intermittent) with the patient's airways. Theventilation interface includes a pair of nasal inserts made fromflexible, resilient silicone which are oval shaped in cross-section andslightly tapered from a base proximal the ventilation supply to thedistal tip end. A bead flange is disposed about the exterior of eachinsert at the distal end of the insert. A bleed port for release ofexhaled air is defined through a conical vent projecting normally to thepath of the incoming air flow, and continues through a nipple extendingto the exterior of the air conduit. In one embodiment, a pair of nasalinserts are integral with a nasal cannula body, with bleed ports axiallyaligned with each insert. In another embodiment, each insert isindependently connected to a separate, thin-walled, flexible supplyline.

Advantageously, the construction of the nasal inserts permits theventilation interface to be retained in the patient's nares withoutrequiring a harness, head strap, or other-retaining device. The nasalinserts do not merely seal the base of the nostrils, but are insertedinto the nostrils farther than nasal pillows, as far as the nasalmucosal membrane, and are retained by resilient expansion of theinserts, the flanges engaging notches in the nares, together with thepressure of incoming air, which forms a positive seal to prevent theleakage of air past the inserts. The nasal inserts are constructedaccording to specifications which permit the inserts to be relativelythin-walled, and are oval shaped in cross-section to conform to theshape of the nostrils. This construction permits the nasal inserts tohave a large internal diameter in order to pass a greater volume of airthan nasal pillows or prongs, without significant narrowing of the airpassages, thereby maintaining lateral pressure, and avoiding drying andburning of the patient's nasal passages, as well as supplying asufficient number of air molecules at the desired pressure to keep thepatient's airways patent. Consequently, the ventilation device is morecomfortable for the patient to wear while sleeping than conventionalpositive airway pressure devices, but at the same time is more effectivein treating the patient's apnea.

The bleed ports are specially designed to avoid the whistling noisescommonly experienced with conventional nasal masks and nasal pillows. Byprojecting the vent structure into the air passage normal to thedirection of the air flow from the supply tubes, incoming air must turnninety degrees and exit through a long, restricted diameter bleed portto vent to the atmosphere, eliminating whistling noises to increasepatient comfort. In the embodiment having a nasal cannula body, thebleed ports are axially aligned with the nasal inserts, providing CO₂with a direct path to exit the cannula body. When the nasal inserts areattached to independent supply tubes, the bleed ports are at the base ofthe nostrils, providing essentially normal exhalation.

When the nasal inserts are directly connected to the supply tubes, thenasal inserts may be even more thin-walled than when attached to acannula body, resulting in an even greater volume of air suppliedthrough the cannula body, up to a 20% increase in volume. In this casethe supply tubes may be similar to heat-shrink tubing, being made from avery thin-walled thermoplastic is material that is lightweight andflexible so that the supply tubing may collapse when not in use, butwill expand to a predetermined diameter under pressure applied by aventilator.

Accordingly, it is an object of the invention to provide a ventilationinterface for sleep apnea therapy having nasal inserts which sealagainst the nares and do not require a harness, head strap, or otherexternal devices to maintain pressure for retaining the inserts in oragainst the patient's nostrils.

It is another object of the invention to provide a ventilation devicehaving nasal inserts made of flexible, resilient plastic with a beadflange for retaining the inserts in the nares, wherein the walls of theinsert are thin-walled and maintain lateral pressure in the nares inorder to provide a greater internal diameter for the delivery of agreater volume of air molecules at a constant delivery pressure andwithout forcing ventilation gases through restricted ports orpassageways so that drying and burning of the patient's nasal airways isavoided while delivering a therapeutic volume of air to maintain theapneic patient's airways in a patent condition.

It is a further object ventilation interface for sleep ports to avoidwhistling noises at the interface a vent passage for expired air.

Still another object of the invention is to provide a ventilationinterface which is lightweight and comfortable so that the apnea patientis not tempted to discard the ventilation device is while sleeping.

It is an object of the invention to provide improved elements andarrangements thereof for the purposes described which is inexpensive,dependable and fully effective in accomplishing its intended purposes.

These and other objects of the present invention will become readilyapparent upon further review of the following specification anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front environmental view of a ventilation interface forsleep apnea therapy according to the present invention.

FIG. 2A is an exploded elevational of a ventilation interface accordingto the present invention.

FIG. 2B is a perspective view of a ventilation interface embodied in anasal cannula body according to the present invention.

FIG. 3 is a section view along the lines 3-3 of FIG. 2A.

FIG. 4 is a section view along the lines 4-4 of FIG. 2A.

FIG. 5 is a section view along the lines 5-5 of FIG. 2A.

FIG. 6 is a perspective view of an embodiment of the ventilationinterface with the nasal inserts incorporated into independent supplytubes.

Similar reference characters denote corresponding features consistentlythroughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a ventilation interface for sleep apneatherapy, designated generally as 10 in the drawings. The ventilationinterface 10 provides an interface for connecting a ventilation devicewhich provides positive airway pressure (either continuous, bilevel, orintermittent) with the patient's airways. As shown in FIGS. 1 and 2A,the ventilation interface 10 includes a conventional adapter orY-connector 12 having a first end adapted to receive a supply hose 14from a mechanical ventilator (not shown) and a second end having a pairof ports 16 with barbed connectors for attachment to two supply tubes18. Supply tubes 18 may be, e.g., 0.3125″ ID (inside diameter) flexchemtubing, made of polyvinyl chloride or other conventional gas supplytubing. For sleep apnea therapy, the mechanical ventilator will usuallysupply room air at a pressure of between five and fifteen centimeters ofwater. The room air may be supplemented with oxygen if desired bysplicing an oxygen supply line into supply hose 14 or using a tripleport connector in lieu of Y-connector 12. It is normally unnecessary tohumidify or add moisture to the air supplied by the mechanicalventilator in using the ventilation interface 10 of the presentinvention, as the interface 10 is designed to avoid stripping moisturefrom the nares, so that moisture does not have to be added to relievepatient discomfort from drying or burning sensation in the nasalairways.

In the embodiment shown in FIGS. 1 and 2A, the ends of the supply tubesdistal from the Y-connector 12 are attached to opposite ends of a nasalcannula body 22 by barbed connectors 20. Barbed connectors 20 preferablyhave an inside diameter substantially equal to the inside diameter ofsupply tubes 18 in order to prevent any constriction or narrowing of theair passage which may cause increased velocity in air flow. Nasalcannula body 22, described more fully below, has a pair of nasal inserts30 which are inserted into the nares of the patient P). The supply tubesmay be looped over the patient's ears and joined to the Y connector 12,which may be suspended at about the patient's chest level when thepatient is standing, as shown in FIG. 1. For Bi-level Positive AirwayPressure (BiPAP) or Intermittent Mechanical Positive PressureVentilation therapy, a suitable valve may be connected between thesupply tubes 18 and the cannula body 22. An exemplary valve is describedin the Applicant's prior application Ser. No. 09/524,371, filed Mar. 13,2000, which is hereby incorporated by reference in its entirety.

The nasal cannula body 22 is shown in greater detail in FIG. 2B. Thecannula body 22 is an arcuate, hollow, body having substantially flattop wall 22 a and flat sidewalk 22 b merging with a semi-cylindricalbottom wall 22 c defining an air chamber 22 d (seen more clearly in FIG.3) for the passage of air and other gases, and having cylindrical tubes24 at opposite ends which receive one end of the barbed connectors 20. Anotch 26 is defined transversely across the top wall 22 a of the cannulabody 22, defining a pair of mounting pads 28. A pair of nasal inserts 30are formed integral with the mounting pads 28. The nasal inserts 30 arehollow and form a continuous flow path or conduit for the passage ofinhaled and exhaled gases between the patient's nasal air passages andthe air chamber 22 d.

The nasal inserts are shown in greater detail in FIGS. 3, 4, and 5. Thenasal inserts 30 are substantially oval in cross-section, with the majoraxis substantially parallel with the notch and the minor axis normal tothe notch. The nasal inserts 30 taper slightly from a wide base 32proximal the cannula body 22 to the open distal tip ends 34. The nasalinserts 30 have a flange 36 about the distal tip ends 34 on the exteriorsurface of the inserts 30, which may be formed as a semi-cylindricalbead.

The cannula body 22, including the nasal inserts 30, are preferably madefrom silicone elastomer. The cannula body 22 or air chamber 22 d has aninternal diameter of at least 0.3125 inches throughout its length. Thewalls of the nasal inserts 30 may be thinner than the top wall 22 a. Thethickness of the walls of the nasal inserts 30 are preferably betweenabout {fraction (1/32)} and {fraction (1/20)} inches. The thickness ofthe walls at the flange 36 may be about {fraction (1/16)} inches. Thehardness of the walls of the nasal insert 30, as tested on a type AShore durometer, may range between about 15 and 40, preferably about 30.If the walls of the nasal inserts 30 are made any thinner, they willfail to have sufficient integrity, and if made any thicker, they willhave insufficient flexibility to form a seal against the pares. Thethinness and softness of the nasal inserts 30 make them virtuallyunnoticeable while in the nostrils. For an adult patient, the nasalinserts may have a height of between about 0.25 and 0.75 inches. Theinternal diameter of the nasal inserts 30 may measure about 0.75″ on themajor axis and 0.5 on the minor axis, allowing for generous laminar airflow and delivering pressure more by volume of air molecules thanvelocity of air flow, and deliver about double the volume of nasalpillows, which have a round internal diameter of, for example, about0.25 inches. Nasal pillows cannot be made with such large internaldiameters, because it becomes difficult to create a seal under thebottom of the nose, as the pillows would have an internal diameterlarger than the internal diameter of the nares, and the pillows are notas flexible as the nasal inserts 30 of the present invention.

In use, the nasal inserts 30 are inserted up the patient's nostrilsuntil the flanges 36 lodge against the mucous membranes. As such, thenasal inserts 30 are considered an invasive device. Testing hasconfirmed that the nasal inserts 30 are biocompatible and meetregulatory requirements. The nasal inserts are retained in the patient'snares by the flanges 36, by the flexibility and resiliency of thesilicone elastomer, and by lateral pressure of the room air, which ismaintained at between five and fifteen centimeters of water. The ovalcross-section of the nasal inserts 30 is shaped to conform to thenormally oval shape of the nares. The relative large internal diameterof the nasal inserts 30 permits air to be supplied to the patient'sairways in sufficient volume at the driving pressure withoutaccelerating the rate of airflow that the patient has sufficientpositive airway pressure to be of therapeutic value in maintaining thepatient's airways patent during an episode of obstructive apnea withoutdrying the nasal passages. The notch 26 in the top wall 22 a of thecannula body 22 lends additional flexibility to the cannula body 22, sothat the nasal cannula 22 can be adjusted for deviated septums, thickseptums, and other anatomical variations in the configuration of thenostrils.

The cannula body 22 has a pair of bleeder ports 38 disposed in thebottom wall 22 c directly below and axially aligned with the nasalinserts 30. The bleeder ports are formed by an upper conically shapednipple 40 extending upward into the air chamber 22 d, and a lowerconically shaped nipple 42 extending below the bottom wall 22 c.Conically shaped nipple 42 further has a distal end with an opening thatcan be substantially oval in shape. The bleeder port has an internaldiameter of about three millimeters and extends for a length of about0.25 inches. The upper nipple 40 extends about 0.125 inches into the airchamber 22 d. The internal diameter of the bleeder port 38 is ample topermit venting of carbon dioxide exhaled by the patient while not beingso large as to cause a significant pressure drop in the cannula body 22,and axial alignment of the bleeder port 38 with the nasal inserts 22creates a direct path for venting of the expired gases. At the sametime, laminar flow of air supplied by the supply tubes is normal to thebleeder ports 38, so that air supplied by the ventilator must bendninety degrees to exit through the elongated bleeder port 38. The effectof this construction is that the bleeder port 38 is virtually silent inoperation, eliminating the whistle associated with bleeder holes inconventional ventilation interfaces.

FIG. 6 is a generally diagrammatic view of an alternative embodiment ofthe ventilation interface, designated 50 in the drawing. In thisembodiment, each nasal insert 52 is connected to a separate supply tube54, the supply tubes 54 being connected to the mechanical ventilatorsupply hose 56 by a suitable Y-connector 58 or adapter, the cannula body22 and common air chamber 22 d being omitted. The nasal inserts 52 havesubstantially the same construction as nasal inserts 30, being oval incross-section and having a similar height and an annular flange 60 aboutthe distal tip for lodging the nasal insert 52 in a naris. The nasalinsert 52 is also made from silicone elastomer, and has the samesoftness, thickness, flexibility and resilience as the nasal insert 30.In this configuration, since the inserts are not connected to thecannula body 22, the angle at which the inserts 52 enter the nostrils isnot restricted by the cannula body 22, and therefore the nares canaccept a greater displacement, and may accommodate a 20% greater volumeof air molecules through the insert 52 than the insert 30.

In this embodiment, the supply tubes 54 may be made from a flexible,lightweight, but relatively inelastic thermoplastic material, similar toheat shrink tubing, so that the supply tubes 54 may be at leastpartially collapsed in the absence of pressure from the mechanicalventilator, but expand to their maximum diameter under a pressure ofbetween five to fifteen centimeters of water. The lightweight of thesupply tubes 54 decreases any pressure on the patient's ears resultingfrom the weight of the supply tubes, increasing patient comfort. Thebleeder ports 62 have a similar construction to the bleeder ports 38,having an internal nipple 65 normal to the axis of the nasal insert 52and an external nipple 64, the bleeder ports 62 being just above thebase of the inserts 52 and normal to the flow of supply air through theinserts 52.

It will be understood by those skilled in the art that the dimensions ofthe nasal inserts 30 and 52, and of the bleeder ports 38 and 62, arerepresentative dimensions for a ventilation interface 10 or 50 designedfor adults, and that the ventilation interface 10 or 50 may be made withcorrespondingly reduced dimensions for teenage children, preteens, andinfants. It will also be understood that the nasal inserts 30 and 52 maybe made from thermoplastic elastomers other than silicone, providingthat the material has similar softness, resilience, flexibility, andbiocompatibility. It will also be understood by those skilled in the artthat the nasal inserts 30 and 52, although illustrated in conjunctionwith ventilation devices for the treatment of sleep apnea, may be usedin any other application where it is desirable to have an interfaceforming a seal between at person's nasal airways and a ventilation orgas collection device, including, but not limited to, rescue breathingapparatus used by firefighters and other emergency personnel, scubadiving tanks, etc.

It is to be understood that the present invention is not limited to theembodiments described above, but encompasses any and all embodimentswithin the scope of the following claims.

1. A ventilation interface, comprising: (a) a nasal cannula, the cannulabeing a hollow, arcuate body and a semi-cylindrical bottom wall definingan air chamber, the body having cylindrical tubes at opposing ends ofthe body adapted for connection to ventilator supply tubes; and (b) apair of hollow, flexible, resilient nasal inserts, each nasal inserthaving a base end connected to the top wall of said nasal cannula and anopen distal tip end, each nasal insert being oval in cross-section anddefining a conduit forming an air passage in communication with said airchamber, each said nasal insert having a flange formed as a beaddisposed about the distal tip end; (c) wherein each said nasal insert iscapable of being compressed and inserted into a patient's naris to apatient's mucosal membrane and being retained therein solely by saidflange, by the resilience of said nasal insert, and by lateral pressureagainst the naris from ventilator air flow through each said nasalinsert.
 2. The ventilation interface according to claim 1, wherein saidnasal cannula and each of said nasal inserts is made from silicone, saidnasal inserts being formed integral with said nasal cannula.
 3. Theventilation interface according to claim 1, wherein each said nasalinsert has an internal diameter of 0.75 inches on a major axis and 0.5inches on a minor axis.
 4. The ventilation interface according to claim1, wherein each said nasal insert has a wall thickness between about{fraction (1/32)} and {fraction (1/20)} inches.
 5. The ventilationinterface according to claim 1, wherein each said nasal insert has asoftness measuring between about 15 and 40 on a type A Shore durometer.6. The ventilation interface according to claim 1, further comprising:(a) a pair of barb connectors; and (b) a pair of supply tubes, saidsupply tubes being connected to the cylindrical tubes at opposite endsof said nasal cannula by said barb connectors.
 7. The ventilationinterface according to claim 6, further comprising a Y-connector havinga first end adapted for connection to a ventilator supply hose, and asecond end having a pair of ports connected to said supply tubes.
 8. Theventilation interface according to claim 1, wherein the top wall of saidnasal cannula has a notch defined therein parallel to and disposedbetween said nasal inserts for increasing flexibility of said nasalcannula in order to bend said nasal cannula to conform to a patient'snostril configuration.
 9. The ventilation interface according to claim1, further comprising a pair of bleeder ports defined through the bottomwall of said nasal cannula, each said bleeder port being axially alignedwith a separate one of said nasal inserts, further including an uppernipple projecting into said air chamber and a lower nipple dependingfrom the bottom wall of said nasal cannula, the bleeder port beingdefined through said upper and lower nipples, and the bleeder portfurther having a substantially oval distal end.